1. Field of the Invention
The present invention relates to a system which prevents spilling from containers during filing thereof, and, more particularly, to a system which disables a fluid dispensing apparatus when either the container into which the apparatus is to dispense fluid is full or if one or more caps for closing filing apertures in the container are not in place.
2. Description of the Related Prior Art
When filling a tank with a spillable substance, for example, a liquid, spilling can occur when the tank is overfilled by dispensing too much of the spillable substance into the tank so that the substance exits from apertures in the tank, such as filling and/or venting apertures. In addition, spilling can occur when one or more apertures in the tank, other than the aperture through which the tank is being filled, are not properly capped, or otherwise closed off, to contain the substance in the tank so that during filling of the tank, the substance is able to leak out of the uncapped aperture(s).
Problems presented by inadvertent spillage during filling operations can be particularly acute in the case of diesel-powered train locomotives.
Because of the large capacities of the fuel tank of most locomotives (typically 1000-5000 gallons) it is desirable to dispense fuel into the tank at high volume rates so as to fill the tank as expeditiously as possible. Present fuel dispensing apparatuses dispense fuel at rates ranging from 150 to 350 gallons/minute, and future systems may dispense fuel at rates of up to 600 gallons/minute. In addition, diesel locomotives tanks typically have multiple filler openings so as to accommodate filling from either or both sides of the tank and may also include one or more air vent openings disposed near the top of the tank to allow air into and out of the tank.
If the tank is being filled at one filler opening and another filler opening is not properly capped, fuel can exit the uncapped opening while being dispensed into the tank. Alternatively, if the level of the fuel in the tank reaches the top of the tank, fuel can exit from one or more of the air vent openings. The problem of spillage in train locomotives is exasperated by the fact that railroad tracks are typically not completely level and one side and/or end of the tank may be disposed at a lower position than an opposite side and/or end of the tank. Accordingly, during a filling operation, fuel may reach the level of a lower filler opening before it reaches the level of the opening at which the tank is being filled.
Due to the high volume rates at which fuel is typically dispensed into a locomotive fuel tank, any spillage which occurs during the refueling process can result in substantial quantities of fuel being spilled upon the ground, thus posing safety, health, and environmental hazards.
Typically, spilling is avoided by nozzles with automatic shut-offs and/or by fuel gauges or view windows provided in tanks which permit operators to visually monitor fuel level in the tank. Neither method, however, monitors whether all unused filler openings are capped and neither method accounts for tank tilt. That is, if a nozzle with an automatic shut-off capability is being used at one filler neck and a different, uncapped filler neck is disposed at a lower position than the nozzle due to tank tilt, fuel may reach and exit the uncapped filler neck before the level in the tank reaches the automatic shut-off sensor of the nozzle. In addition, automatic shut-offs may sometimes malfunction. Fuel gauges are often broken due to the harsh environment in which a locomotive operates and is serviced. View windows often become occluded by dirt, snow, or other debris or even by diesel fuel staining so as to become non-functional. In addition, a gauge or view window may also suffer from the same disadvantages as an automatic shut-off nozzle if an uncapped filler neck is disposed below the gauge or window due to tank tilt. Moreover, monitoring fuel level through a view window by a gauge inherently requires the vigilance of an operator, which may not be reliable if the operator is inattentive or becomes distracted.
Various systems have been proposed in the prior art literature for automatically avoiding spillage during the filling of a liquid container.
For example U.S. Pat. Nos. 5,349,994; 5,460,210; and 5,515,890 to Koeninger disclose a system for preventing the overfilling of tanks, especially fuel trailer tanks. The system includes top sensors and bottom sensors provided in each compartment of a multi-compartment fuel tank. The bottom sensors indicate whether there is retained fluid within the tank/compartment, and the top sensors indicate whether the tank is full. When both sensors give a dry signal, fuel dispensing equipment is enabled so that the tanks may be filled. When the bottom sensor is wet, the sensor is automatically or manually overridden so that dispensing may be continued. The top sensors disable the dispensing system when the tank is full. The bottom sensors indicate whether there is retained fluid in the tank so that an operator will know if the tank can accept the full tank capacity amount of fluid. Accordingly, the system disclosed in the Koeninger patents determines whether fluid is retained in the tank before a dispensing operation commences and shuts down the dispensing equipment when the tank is full. The system does not, however, provide any protection in the situation in which a tank having multiple filling openings has openings which are not properly capped or coupled to a fluid-dispensing apparatus.
U.S. Pat. No. 4,915,142 to Schirmacher discloses a monitoring system for filling containers which includes an electrically conductive connecting line connected in series with a measuring device disposed in the container. The connecting line is connected to the tank opening by means of a connecting line flange coupled to a tank opening flange and the line is connected to a pipeline by means of a connecting line flange coupled to a pipeline flange. The interflange connections are electrically insulating connections so that the electrically conductive line is insulated from both the tank and the pipeline. Impedance bridges are provided over the interflange connections to prevent static charge build-up. The measuring device is preferably a cold line system which goes through an impedance change when fluid in the tank reaches the device.
The device and line are electrically connected to a monitoring device which in turn is in operative connection with a control device that actuates a shut-off element. When the tank is not full and no malfunctions are detected along the hose line, the control device opens a shut-off element to permit fluid-dispensing. Dispensing commences until a change in system impedance due to fluid level reaching the measuring device or due to a malfunction along the connection hoses is detected by the monitoring device which sends a signal to the control device which closes the shut-off element. Again, the system proposed in Schirmacher '142 includes no protection to ensure that filling apertures are properly capped or coupled to a dispensing apparatus.